WELLINGTON PHILOSPHICAL SOCIETY.

Evening Post, Volume VII, Issue 250, 27 November 1871, Page 2

WELLINGTON PHILOSPHICAL SOCIETY.

A meeting of this .society—the last of the season—was held on Saturday evening, in-the Maori House attached to the Colonial Museum, at eight o'clock, Dr. Hector in the chair., ; -~ 'I ■■ : * • < S

The Chairman announced that in accordance with the rules of the 'New, Zealand Institute, the society had to nominate one gentleman not resident in the Colony—one of five that would be nominated by the various y societies _, in {New s Zealand—from whom his Excellency would select three to be honorary, members of the institute. The council had consulted together, and agreed as to a gentleman whose name should be be suggested to the meeting, but before putting it he would wish anyone present who had a candidate to propose to do so. No one proposing a candidate, the Chairman said he would propose Mr. Charles Darwin, a gentleman whose position in the scientific world was well known. He was not merely a man of high scientific attainments, but had made his reputation ' by' discoveries respecting the formation of coral reefs in the - Southern' Seas, and had, moreover, 'in Ms travels, visited New Zealand.- ; ,>.;!->*/.•> ■->::■ iV"i' "' • Mr. Kebbell seconded the proposal, and Mr.. Darwin was unanimously elected. ; • ■• The Chairman said lis had to anaonnce that the library of; the institute had been increased" by the! donation of some very desirable works, among which was a complete set ;of the transactions of the" Zoological Society, which included a most valuable paper, with illustrations, upon the moa, by Professor Owen. He also said he had hoped that a gentleman would have been present, to give an account of the fish which'had lately/been clast^upipn|tlie coast by'Terawiti. K'e miglit remark that among the millions which have been heaped up by the action of th 6 sea, there were none of those commonly caught in the harbor, and there *were< four kinds new to science. The Chairman read a paper, which he had received in the form of a letter, by Mr. B. H. Darnell, of Nelson, on stone im-

pleinents of Africa. In reference to some remarks made in the paper, Dr. Hector said that in the Middle Island, far from the coast line, stone flakes had been. fonnd in abundance, and that in all ■probability stones had been used in cooking ",by the Maoris, and had been 'flaked by being drenched when hot with water. A number of specimens of stone flakes, remnants of a larger collection which was sent to -Vienna,* found bywMT.tDarnell on-the Cape flats, were exhibited. A paper, by Mr. Skey, on the cause of the suspension of clay in water, and its precipitation .by. certain substances, with notes upon Professor Ye'vons' theory in relation thereto, was next read. He showed that clay is capable of combining free—such as distilled water—in which* state it remains suspended for an indefinite; time, and that the precipitating effects of the salts and acids are due to^the exercise of their "affinity for water. These affinities being superior to those of clay for the same liquid, the clay is dehydrated, and thus brought into a condition resembling that of ordinary'clay,/■both- 'physically !andl chemically, in which state it" loses its diffusive power. Sulphuric acid has'the greatest precipitating effect upon clay in water, one part of it' to 25,000. parts of the mixture being^ effective.- Generally spring water is sufficiently charged with salts to effect the clarifying of clay water in about 24 hours. A solution of magnesia soon clarifies such water;? though it; requires 7000 parts ••of-" such? prater sto dissolve it; The author showed how water may thus be purified for use. He also demonstrated how most, if not all natural clays, if only mixed with small quantities of water do riot, remain persistently suspended. This he attributes' to the presence sometimes of salts, sometimes of carbonic acid. He then showed that clay, brick, &c., or any other kind of indurated clay is resolvable into the most hydrated clay direct .by; pulverizing it in pure water. He next discussed Professor Yevons' theoryas broached in the London ChemicaL.News,. under, the, heading, *' Oh the so-called molecular movements of microsopic particles," which . at--tempts' to explain,' the . phenomena as. attributable to the agency of electricity. : - Mr. Skey shewed'that thi3 theory was theoretically and experimentally incompetent to explain these phenomena, in the case of clay at least, if not for the other cases ; but they are susceptible of an easy and very plausible explanation on the assumption of a very large quantitative affinity of this substance for water, but an affinity of a very weak intensity, so weak that most of the common;saltsjare ? able;to overcome! it, and so; remove the clay as a chemical precipitate. Mr. Mantell asked Mr. Skey whether he could explain how it was that a tub of by. no means clear wafer in" his garden, which was used to wash clay pots in, was invariably cleared by* the water which poured i into it during a heavy shower of rain. Mr. Skey not replying, Dr. Hector ex.-> plained that if the water which cleared th 2 tub was caught on an iron roof, the slight amount of acid in it might produce the clarifying effect. He stated; that, Miv Skey's paper was most valuable, as, 'if his theory were correct, it would point to a means of clarifying clayey water with so small a proportion of acid as would not affect the water perceptibly either to the taste or for ordinary purposes. A paper by Mr. Skey was next read, on a form of electro-magnetic seismograph, .adapted for exhibiting or registering minute shocks of earthquake. r ■ Dr. Hector remarked that the instruments at present in use were very faulty, and that Mr. Skey's seismograph would be so very sensitive that even a gust of wind blowing against a-house would be registered by it. The next paper read was onNew Zealand chitonidKY by Captain P. W. Button, which was illustrated by a collection, some of which had been collected by the author. The paper commenced- with a general description of the chitons, which form, a distinct family 'of the Jmollusci, easily; recognised by their oval or oblong form, covered by several shelly plates or valves, which give them something the appearance, of those isopod crustaceans, commonly known as wood-lice. The animal is of an oval or oblong shape, . with a long and broad foot, rounded at each end. The head is not furnished with eyes nor with tentacles, but has a waved membraneous hood surrounding the mouth. The tongue is long, spirally rolled, and armed with hooked horny teeth. The breathing organs are in the form of a! series of small triangular leaves, and are situated in a row on each side of the body, between the mantle and the foot. The habits of the chitons, as far as they are known, were described, and suggestions as to • the best method of collecting and preparing them as specimens were given. Chitons are found in all countries, but are not so abundant in the Northern Hemisphere as in.the Southern ; nor on the shores of the Atlantic as on those.of the. Pacific ; neither are they so common nor so large in cold latitudes as in warm—the sub-tropical portion of the South Pacific appearing to be their headquarters. In England, 'only about a dozen species have been, found, while 21 are described (the author appended to his paper a list of their descriptions) as already known to inhabit New Zealand— and probably many move are yet to be discovered, for few- people have collected them. Altogether, nearly 300 spscies arc now known to science. ,-In a fossil'state about' 24 species have been found, some of them dating as far back as the Upper Silurian period. This concluded the business before the society, and the meeting" dispersed. Dr. Hector announced that the next meeting would be the annual one, which would be held about January, next.., : r' ; '